One third of Apple's U.S. sales in 2013 were to Americans making more than $100,000 a year, and of that group, Apple's share was 65%, according to NPD (which did not provide a spreadsheet supporting that number).

The bad news is that the cream of the U.S. market is also the segment that is growing most slowly – only 4% year over year according to NPD.

The fastest growing segment – people making under $30,000 a year – grew at 42% a year, double the industry rate. Only 20% iPhone sales went to that segment of the market, compared with 35% for Samsung.

Selling phones or more accurately, selling a truckload of phones specifically to those under $30K means selling a phone with next to zero margins, and Tim Cook has made it clear that Apple doesn't give a lick about doing that:

“We’re not in the junk business.” The upper end of the industry justifies its higher prices with greater value. “There’s a segment of the market that really wants a product that does a lot for them, and I want to compete like crazy for those customers,” he says. “I’m not going to lose sleep over that other market, because it’s just not who we are.